Launch date changes approved – Atlantis performing without issue

February 14, 2008 by Chris Bergin

STS-122’s Flight Day 8 has consisted of PAO events and waste disposal activities – earning it the unglamorous title of “dump day” – ahead of preparations for the third and final EVA of the mission on Flight Day 9, which has now begun.

Meanwhile, at Thursday’s Program Requirements Control Board (PRCB) meeting, a number of 2008’s launch dates have been moved slightly to the right, following a refinement of processing flow timelines.

Public affairs events, highlighted by German Chancellor Angela Merkel in-flight call from Berlin with ESA astronauts Hans Schlegel and Leopold Eyharts, were conducted during the on-going transfers between Atlantis and the ISS during Flight Day 8.

Atlantis’ mission is proceeding without issue, with the only problem being worked by the Mission Evaluation Room (MER) in Houston relating to an overexposed video that was downloaded from the middeck – an issue that would normally go without a mention, had it not been for the lack of any other problems.

Mission goals are all on track, with the Mission Management Team (MMT) tasked with refining how much oxygen can be offloaded from Atlantis to the ISS ahead of undocking, with the estimate continuing to rise via reduced power consumption by the orbiter.

This is some achievement, considering Atlantis is now undocking two days later than originally planned, and her lack of the power saving SSPTS (Station-Shuttle Power Transfer System) – which she will gain for her two additional missions after STS-125.

Flight Day 8’s ‘dump day’ – which involves the offloading of waste water from the orbiter – was slightly delayed due to an issue during the parking of the SARJ (Solar Alpha Array Joint).

‘During P3 SARJ parking, toothcrash caused SARJ Shutdown to fail. Normally failure occurs after three failed attempts to lock the SARJ but this time it failed after the first attempt,’ noted MMT information. There appears to have been an Ada exception in the P3-2 MDM during the first recovery attempt.

‘There is a SPN for the TRRJ where this type of failure is considered a ‘nominal failure’ case. As there is no such SPN (yet) for SARJ, the team elected to swap SARJ strings. SARJ took a long time to get in a good configuration. Delayed maneuver and water dump init by about an 1.25 hours.’

Meanwhile, Thursday’s PRCB has approved changes to a number of what is hoped will be six missions this year, based around the delay to STS-122 due to the ECO (Engine Cut Off) sensor system modifications.

Titled ‘Update Launch Dates for STS-125 and subs,’ the presentation deals with the resulting downstream impacts of STS-122’s move to February 7, 2008.

The changes push Atlantis’ next mission (STS-125 to service Hubble) from August 7 to August 28 – although memos note this could eventually move into September – as observed on some planning manifests.

Endeavour’s LON (Launch On Need) rescue role for STS-125 – tagged STS-400 – has a NET (No Earlier Than) launch date of September 4, moving from August 14, although she will take up residence at Pad 39B, for the last time by a shuttle due to the pad’s role for the Ares I-X test flight – ahead of Atlantis’ launch, due to the lack of safe haven at the ISS during the Hubble mission.

Once Endeavour is stood down from her rescue role, she will then undergo a mini rollback, before being placed on Launch Pad 39A for her primary flight, STS-126 – itself a highly interesting logistics flight to the ISS.

According to the PRCB presentation, STS-126 has moved from September 18 to October 16, which also causes STS-119 – with Discovery – to slip to December 4, from November 6.

These changes still allow for six missions in 2008, although it does not take into account an ongoing evaluation at the Michoud Assembly Facility (MAF), relating to production problems with ET-128 – the first tank to have a titanium modification to its Ice Frost Ramps (IFRs).

Lockheed Martin managers are still working on a refined delivery date for the tank, which has been documented several times over the previous month as ‘weeks’ down on its required delivery date that would allow STS-124 to launch in its allotted window in April – with processing timelines showing the launch will be pushed out into May.

‘These dates are based on vehicle processing at KSC. They do not avoid all the manifest constraints,’ added the presentation. ‘Continue to identify constraints, recovery plans, and decision points to prevent negative work and maximize supportability to the space station and HST.’

Refinements to launch dates will – as always – continue to occur over the coming months, though there is no schedule pressure involved. Even if the program sticks to the 2010 retirement date for the fleet, there is enough margin to even allow two of 2008’s flights to slip into 2009 – which is not the case at present, even after STS-122’s delay.

L2 members: All documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, updated live.